1. Field of the Invention
The invention relates to safety bindings for skiing, more particularly safety bindings intended for the practice of ski touring.
2. Background Information
A binding of the aforementioned type must enable the boot to rotate about a transverse axis relative to the ski, located at the front of the boot, when skiing uphill, so that the heel of the user can move away from the ski so that an optimal thrust force can be exerted. Such a binding must also make it possible to dampen substantial torsional forces between the boot and the ski when skiing downhill.
An example of a safety ski touring binding is disclosed in the document DE102007038506. This safety binding is a baseplate, carrying the boot, which is pivotally mounted on the ski at the front and provided at the rear with detachable means for connecting to the ski. This safety binding is adapted to be used with rigid alpine ski boots that are attached to the pivotable baseplate. A toe piece and a heel piece are fixed to the baseplate in order to allow the boot to be retained or, when necessary, releasing it. In the ascent position, the pivotable plate is released from the ski at the rear in order to enable the boot to pivot relative to the ski. A heel lift capable of taking various positions is also provided. In the descent position, the pivotable baseplate is affixed to the ski in order to allow skiing using alpine downhill skiing techniques. Such a binding does not allow one to easily switch from the ascent position to the descent position. Indeed, to switch from the ascent position to the ski position, one must first ensure that the heel lift is in a storage position which does not block the rotation of the baseplate, and then, after setting the baseplate in the low position, one must maneuver the control lever to actuate the locking means. If the heel lift is in the high position at the start of the maneuver, it is necessary to carry out two separate, successive manipulations in order to switch from the ascent position to the descent position.
Another example of a ski touring binding is provided by the document EP1498993, in which the locking means of the baseplate and the heel lift are integral in a single piece. Although such a device can have an advantage in terms of weight, the same is not true in terms of efficiency and performance. Firstly, the disadvantage of the binding described in the previous paragraph is also found in this document. Indeed, to switch form the ascent position to the descent position, one must maneuver the heel lift once, set the baseplate in the low position, and then maneuver the heel lift again to lock. Furthermore, due to the locking means being positioned far to the rear, the forces are poorly transmitted between the user and the ski.
Another example of ski touring binding is given in FIGS. 1 to 6 of the document WO2007/060219, in which the control of the locking means is positioned beneath the boot, so that it is necessary to release the boot from the bindings in order to switch from the ascent position to the descent position. This constitutes a major drawback, because a binding of this type is often used in areas where powdery snow is abundant, and it may be difficult to put the skis back on. In addition, during the ascent on a low gradient slope in powdery snow, the back and forth movement of the baseplate causes the snow to pack in a certain area of the binding. This phenomenon, commonly referred to as a “wedge of snow”, is a major hindrance in this type of binding. The packed snow hardens into ice and is particularly difficult to remove from the hard-to-reach areas, such as around the locking means, for example. However, switching the binding into the descent position is only possible after the snow has been completely removed. It is to be understood that the time required to switch from the ascent position to the descent position with such a product may be particularly long. Furthermore, a binding of this type is practically cumbersome and considerably weighs down the ski.
A description of the problems associated with existing safety bindings is not complete without including the problem relating to the time necessary to switch from the descent position to the ascent position, and especially from the ascent phase to the descent phase being more than a matter of comfort for the user. Indeed, it is a safety issue. This is particularly true because an off-piste skier, more frequently than other skiers, needs to move quickly in leaving his/her location in the case of an avalanche, for example.
Therefore, there is a need for an arrangement to connect the baseplate to the ski that is easy to handle, or manipulate, when switching to the ascent position or to the descent position. There is also a need for a connecting device that optimizes the transmission of forces between the boot and the ski and is substantially rigid in the descent position. The binding must be capable of providing a rigid and solid connection of the boot to the ski and must be sufficiently strong to withstand the forces generated during ski touring, while being sufficiently lightweight.